1. Field of the Invention
The invention relates to an apparatus and method for distributing fire suppressant.
The invention relates more particularly to an apparatus and method for delivering a fire suppressant selected from among one or more available suppressants to any combination of one or more suppressant distributors.
2. Description of Related Art
A variety of materials are known that can suppress fires. In general, these fire suppressants must be distributed in the immediate vicinity of the fire in order to be effective. Several conventional approaches for distributing fire suppressants are known.
First, a single suppressant source may be connected to a single control valve, which is then connected to a distributor that is in the area where suppressant is to be distributed. In response to a fire, the control valve is opened, whereupon suppressant flows from the suppressant source to the distributor, and thus to the fire.
This arrangement, while simple, has a number of disadvantages, one of the more serious being that it a requires a dedicated system for each location, i.e. a source of suppressant must be provided for each area that is to be protected. This is often impractical or undesirable.
It is also known to connect one or more fire suppressant sources with a series of control valves, each control valve being connected with a distributor. Such an arrangement is illustrated in FIGS. 1 and 2.
In the arrangement illustrated, the system 10 includes four suppressant sources 20, 22, 24, and 26. The suppressant sources are all in communication (i.e. via a line, pipe, or tube) with a series of control valves 30, 32, 34, 36, and 38. Each of the control valves connects to a suppressant distributor 40, 42, 44, 46, and 48 (not shown). The arrangement of control valves and connecting lines is sometimes referred to collectively as a discharge manifold.
Each of the control valves in this conventional arrangement defines two apertures therein: 30A and 30B; 32A and 32B; 34A and 34B; 36A and 36B; and 38A and 38B. Each control valve is movable between two positions, closed and open. In the closed position, the two apertures of the control valves are not in communication with one another. In the open position, the two apertures are in communication. Consequently, for the configuration shown, in the closed position the control valves 30, 32, 34, 36, and 38 do not pass suppressant, while in the open position, they do.
FIG. 1 shows all of the control valves 30, 32, 34, 36, and 38 in their closed positions, as might be typical when the system is inactive. FIG. 2 shows control valve 38 in the open position. Given the positions of the control valves in FIG. 2, apertures 38A and 38B are in communication, thus suppressant from one or more of the sources 20, 22, 24, and 26 (depending on which was open) would pass through control valve 38 to distributor 48.
In such an arrangement, multiple distributors in multiple locations can be supplied by a single set of suppressant sources. However, this arrangement also has disadvantages.
For example, when any one of the control valves 30, 32, 34, 36, and 38 is opened, a large part of the manifold that is not utilized for suppressant distribution at that time nevertheless is filled with suppressant. In FIG. 2, suppressant would flow all the way to control valve 30. The portion of the system that is filled, but does not need to be filled, is sometimes referred to as “dead space”. Such an arrangement is undesirable for several reasons.
For example, dead space diverts suppressant from the location where it is actually needed. In order for a fire suppressant distribution system to be effective, it is important that the quantity of suppressant that is discharged from each distributor be predictable to within established tolerances of the desired discharge quantity and discharge time. In a conventional system as shown in FIGS. 1 and 2, portions of the manifold may be unnecessarily filled with suppressant. Although in some cases the dead space in a system may be vented or discharged, in some cases the agent will not immediately discharge within a proscribed time period (i.e. 10 seconds). This affects the operation of the system; the effects must either be ignored and accepted, or compensated for in other ways.
In cases where the amount of dead space is large (i.e. in a large manifold, with long lines between the suppressant sources 20, 22, 24, and 26 and the most distant of the control valves 30, 32, 34, 36, and 38), this may substantially increase the amount of suppressant that must be used when the system is activated. Similarly, the volume of the dead space may be large enough to require an increased pressure at the sources 20, 22, 24, and 26 when activating the system, so as to maintain adequate distribution pressure at the open distributor 38.
Furthermore, after each activation of such a system, it may be necessary to clean and/or service the entire manifold from the suppressant sources 20, 22, 24, and 26 to the most distant of the control valves 30, 32, 34, 36, and 38, regardless of which of the control valves was opened.
There exists a need for a system that enables distribution of suppressant to any of several available distributors, without unnecessarily filling large unused portions of the system during each activation.